After the episode of Korach, B'nei Yisrael continue to challenge Moshe and Aharon's authority. After yet another plague strikes B'nei Yisrael, Moshe is instructed to perform a demonstration that would show, through Divine intervention, the authenticity of Aharon's leadership as kohein gadol. He was told (17:17-18) to gather twelve staves from the twelve leaders of the tribes and to write their names on their respective staves. Aharon's name was to be written on the stave belonging to the tribe of Levi. Later, when the demonstration is performed, the Torah recounts (17:21) that the leaders gave the staves to Moshe - twelve staves with the stave of Aharon among (besoch) them. Throughout the episode, it is unclear whether Aharon's stave was one of the twelve or if it was in addition to the twelve for a total of thirteen.

Ramban, citing an apparent tradition that the Tribes of Israel shall never be counted as more (or less) than twelve, asserts that the stave of the tribe of Levi was one of the twelve. He suggests that to compensate, the tribes of Efrayim and Menasheh were not separate this time but were considered as one tribe under the umbrella of Yoseif. This approach leads to another question. Efrayim and Menasheh had their own independent leaders. Which one's stave was used? Malbim posits that the leader of the tribe of Efrayim was the one whose stave was used as per Yaakov Avinu's command (Bereishis 48:20) that Efrayim be placed before Menasheh at all times.

Netziv, in Ha'amek Davar, challenges Ramban's position. He proposes that there is no problem with counting B'nei Yisrael as more than twelve in this case because the end result of the demonstration was to be that one of the staves would blossom, thus removing the tribe to whom it belonged from the group of twelve. Rather, Aharon's stave was indeed the thirteenth.

Although Netziv does address Ramban’s issue of a maximum of twelve, Ramban’s opinion is based on a textual inference as well. Moshe was commanded to collect the twelve staves and write Aharon’s name on the stave of Levi. We do not find a command to take a separate stave for Levi. Ramban infers, therefore, that the stave of Levi was among the original twelve. Netziv does not address this inference.

Have a good Shabbos and chodesh tov.